known to exist only at Sand Mountain (a large dune located in Churchill County east of Fallon, Nevada)

Life History:

The Sand Mountain blue butterfly (Euphilotes pallescens arenamontana) is in the family Lycaenidae, the gossamer winged butterflies, which includes blue, hairstreak, harvester, and copper butterflies. It has a wingspan of slightly less than an inch when fully expanded.

These butterflies are known for their almost complete dependence upon Kearney Buckwheat; eating the fallen leaves of the plant as larvae, and drinking the nectar of the flowers as adults - however, the adults occasionally feed on other plant species. Like many gossamer winged butterflies, Sand Mountain Blues have a close relationship with ants; in this case, desert carpenter ants feed off a sugary secretion of the larvae - if the larvae also benefit or not is yet to be determined. Once the larvae metamorphose into the pupal stage, rather than remain fixed to buckwheat plant, the chrysalis drops into the leaf litter at the base. Upon reaching adulthood, E. pallescens arenamontana typically measure anywhere between 0.39 in and 0.47 in. The species is not known to migrate, and in fact stays within 200 ft of its host plant. The lifespan of an adult Sand Mountain Blue is approximately one week.

Distribution and Habitat:

This butterfly is known to exist only at Sand Mountain, a large dune located in Churchill County east of Fallon, Nevada. The butterfly is closely associated with its host plant, the Kearney buckwheat (Eriogonum nummulare) which grows within the dune system. This wild buckwheat is the only food source for the butterfly larvae. The larvae grow into pupae, which mature in the layer of leaves that fall from the plant. Kearney buckwheat also provides nectar for adult butterflies during their emergence between mid-July and mid-September. Individual Sand Mountain blue butterflies have a life span of only about a week during this period.

Sand Mountain is public land managed by the Bureau of Land Management as a designated off-highway-vehicle recreation area. A study of aerial photos and satellite imagery has documented a significant loss of vegetative cover since 1979. During this time, visitor use increased from about 5,000 to over 35,000 visitors annually.

Threats:

Small geographical distribution around the Sand Mountain dune; off-road vehicles